The FDA has received reports associated with the use of these devices in the treatment of unruptured brain aneurysms that suggest some events of peri-procedural stroke and/or death may have been related to procedural risks or patient selection related factors. These factors include patients who had serious co-morbidities resulting in a reduced life expectancy, or who were intolerant to required anticoagulation or anti-platelet therapy.

https://www.fda.gov/Safety/MedWatch/SafetyInformation/SafetyAlertsforHumanMedicalProducts/ucm607024.htm